1997 Fiscal Year Final Research Report Summary
Experimental Study on Nonlinear Phenomena Caused by Ponderomotive Force of Low Frequency Fields
| Project/Area Number |
08680497
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
プラズマ理工学
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| Research Institution | Utsunomiya University |
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Principal Investigator |
HONZAWA Tadao Utsunomiya University Faculty of Engineering, Professor, 工学部, 教授 (20023707)
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| Co-Investigator(Kenkyū-buntansha) |
SAITOU Yoshifumi Utsunomiya University, Faculty of Engineering, Assistant, 工学部, 助手 (70251080)
NAGASAWA Takeshi Utsunomiya University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (10118440)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Low Frequency Fields / Ponderomotive Force / Envelope Shocks / Ion-Beam-Plasma systems / Wave Packets / Nonlinear Modulation / Nonlinear Phenomena |
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| Research Abstract |
In the trem of 1996-1997, we have obtained experimental results as follows. (1) The evolution in the envelope form of large amplitude ion-acoustic waves in plasmas was studied in detail. In this experiment we found that the wave ecvelope steepened at its leading edge during propagation and, as a result, the envelope shock was possibly formed at large amplitudes. Since the dispersive character of the wave and its nonlinearity have only effects to make the slope of the envelope form more gentle, they can not cause the "steepening". From this reason, we concluded that the ponderomotive force of the wave playd an important role for the "steepening" and also for the envelope shock formation. (2) In the second experiment we studied on the nonlinear modulation of waves in ion-beam-plasma systems. The waves were found to suffer nonlinear modulation and to split into a series of many wave packets at large amplitudes above a "threshold". In these processes we found an assymmetry in the wave form between on the upstream and downstream sides. This "assymmetry" was concluded to come from the ponderomotive formce of the wave moving in a plasma.
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